The following discussion of the background of the invention is merely provided to aid the reader in understanding the invention and is not admitted to describe or constitute prior art to the present invention.
6-Monoacetylmorphine (6-MAM, also known as 6-acetylmorphine or 6-AM) is one of three active metabolites of heroin (diacetylmorphine), the others being morphine and morphine-6-glucuronide. 6-AM is rapidly created from heroin in the body, and then is either metabolized into morphine or excreted in the urine. Since 6-AM is a unique metabolite to heroin, identification of 6-AM is considered to be definitive evidence of heroin use. This is significant because on a urine immunoassay drug screen, the test typically tests for morphine, which is a metabolite of a number of legal and illegal opiates/opioids such as codeine, morphine sulfate, and heroin. 6-AM remains in the urine for no more than 24 hours so a urine specimen must be collected soon after the last heroin use, but the presence of 6-AM guarantees that heroin was in fact used as recently as within the last day.
In developing a binding assay for 6-AM, the artisan must consider that samples may contain these metabolites of opiates/opioids. Thus, immunogenic and label conjugates should be designed to present 6-AM so as to provide an assay with minimal cross-reactivity to morphine, morphine-3-glucuronide, morphine-6-glucuronide and other opioids. Analogs for use in preparing such conjugates should also be designed to provide convenient attachment to various proteins, polypeptides, and labels under mild conditions.